Circular  No.  99. 


United  States  Department  of  Agriculture, 

BUREAU   Ol     KNTOMOLOG 
L.  O.   HOWARD.    KntomolqgUt  and  Ch 

THE  M  I    w i r\ 

Bj       I  II        I   'ill  I    I  I    M'KN.      fi 

I  \  I  BOD1  i   I  i"\. 

Nut-growing  in  tin-  United  States  would  in-  a>i<m-ii  u|*>re  rtp*iiiai>l. 
in d ust n  were  it  not  for  the  insects  which  inhabit  t  heTTTTieT-.  render 
them  until  for  food.     This  is  especially  true  of  the  chestnut  and 

chinquapin  and  to  ;i  lesser  extent  of  | an,  hickory,  and  hazel  nuts; 

while  others,  which  include  butternuts,  walnuts,  and  almonds,  suffer 
little  or  no  injury  from  this  source.  Considerable  diminution  in  the 
yield  of  1 1 1 : i n \  forms  of  nuts  is  ; » I  — « »  caused  by  the  inroads  of  insect 
larvae  in  the  growing  husks.  Examples  of  the  first  class  are  the  chest- 
nut "  « orms  "ur  weevils;  of  the  second,  the  husk- worms  and  walnut 
curculio.     The  present  paper  will  be  restricted  to  a  consideration  of 

the    weevil-. 

The  chestnut  crop  suffers  the  greatest  loss,  and  the  chief  depredators 
are  the  grub  like  "  worms  "  or  larvse  with  which  everyone  i-  too  dis- 
tressingly familiar.  These  larvae  develop  vi  ith  the  nuts,  so  that  those 
which  first  attain  maturity  are  read}  to  leave  and  enter  the  ground 
nearly  as  soon  as  the  nuts 
are  gathered ;  others  re- 
main in  the  nuts  some 
weeks  later;  so  it  fre 
quently  h  a  p  \> e  n  -  that 
when  nni-  are  !>;ic  U  e  il 
for  shipment  in  bags  or 
barrels,  some  nuts  which 
ueiv  apparently  sound 
when  shipped  are  found,  <>n  reaching  their  destination,  with  one  or 
more  holes  in  their  shells  (fig.  I),  while  the  repulsive  grubs  crawl 
about  at  the  bottom  of  the  receptacle.  II  "\\  to  cope  with  these  weevils 
has  long  been  a  most  vexatious  problem. 

I'm    ( "ill- i  \  i  r   Wi  EVILS. 
In  comparatively  recent  years  chestnut  culture  has  assumed  consid- 
erable proportions,  and  has  taken  a  new   impetus  since  the  extensive 
introduction  and  development  <>t"  .lapane-r  ami  European  varietie- 

I 
ma 


lan  "  ii  i  anthoi  - 


itnxliirtion  ami  development  ol  .iapane-r  ami  iMiropeati  varietie- 
Tiese  are  grafted  on  American  seedling*  or  name  -jo-  L-.  and  thu 
ianv  valueless  tree-  on  equally  nnproinit-mu  -mTiHv  ronverte.II  int 


'Reprinted  from  Tearbook  "f  the  Departmi  JgHcaJtijre^for  1901,  \>p. 

299  310,  I'ls.  XX \  III   3 
[Clr.  :>o] 


xxx.  tezl  Bga  I  i 


US  DEPOSITORY 


sources  of  profit.  Were  it  not  for  the  "worms."  "borers/'  and 
"blights,"  chestnut  growing  might  develop  into  a  most  lucrative  in- 
dustry in  regions  adapted  to  it. 

Estimates  of  losses. — A  fair  estimate  of  the  damage  done  annually 
by  weevils  to  chestnuts  grown  in  the  Tinted  State>  would  probably 
fall  little  short  of  ->.">  per  cent,  while  in  some  years  the  percentage 
exceeds  that  figure,  running  as  high  as  40  or  50  per  cent.  Growers 
in  some  localities  report  no  damage,  others  place  losses  as  low  a-  ."> 
or  10  per  cent,  while  instances  are  cited  of  whole  crops  being  de- 
stroyed. The  amount  of  loss  is  dependent  on  locality,  season,  and 
to  a  more  limited  extent  on  the  variety  of  nuts  grown.  The  greatest 
damage  is  usually  incurred  in  regions  where  chestnuts  have  grown 
wild  for  many  years,  and  the  least  where  there  are  no  wild  chestnuts 
or  chinquapins  and  the  nuts  are  grown  only  for  market  and  are  care- 
fully gathered.  The  most  extensive  losses,  judging  from  available 
sources  of  information,  appear  to  be  in  Massachusetts,  Pennsylvania, 
New  Jersey.  New  York  (in  the  vicinity  of  New  York  City).  Delaware. 
Maryland.  Virginia,  Tennessee,  and  North  Carolina. 

In  Georgia.  Spanish  and  Japanese  varieties  have  been  cultivated  for 
years  without  attack  by  weevils  being  noticed.  In  New  Jersey.  50  per 
cent  of  the  same  varieties  have  been  ruined.  A  grower  in  Missouri 
has  reported  no  damage  to  50  trees  of  an  American  variety:  another 
at  South  Haven.  Mich.,  has  reported  no  injury  for  a  period  of  three 
or  four  years  to  Japanese  and  Spanish  chestnuts  grown  there,  while 
from  5  to  '20  per  cent  of  the  crop  of  native  nuts  was  annually  de- 
stroyed. The  nearly  complete  destruction  of  the  chestnut  crop  of 
New  Jersey  for  1803  was  reported. 

The  species  oe  chestnut  weevils. — The  species  of  weevils  which 
infest  chestnuts  are  two  in  number— the  larger  chestnut  weevil,  Tiahi- 
ninus  proboscideus  Fab.,  and  the  lesser  chestnut  weevil.  B.  rectus  Say. 
They  have  extremely  long,  slender  beaks  or  snouts,  nearly  as  fine  as  a 
horsehair,  and  considerably  longer  than  the  body  in  the  female.  By 
means  of  this  long  beak  the  female  is  able  to  penetrate  the  thickest  burr 
of  the  chestnut  with  its  long  spines  and  to  cut  out.  with  the  minute  and 
sharp  mandibles  at  the  tip  of  her  beak,  a  little  hole  for  the  deposition 
of  her  eggs.     These  are  inserted  through  the  husk  into  the  growing  nut. 

The  two  species  resemble  each  other  greatly  in  color  and  in  .mark- 
ings, the  general  color  of  both  being  golden  yellow,  ochraceous,  or  clay 
yellow,  frequently  tinged  with  olive,  and  a  little  paler  on  the  lower 
surface.  The  disk  of  the  thorax  is  a  little  darker,  with  a  wide  bright 
band  on  each  side,  and  the  elytra,  or  wing-covers,  are  mottled  with 
rich  light  brown  or  dark  brown  markings  of  variable  size  and  extent." 

"Occasional  individuals  lack  the  darker  markings,  some  being:  paler,  others  darker,  even 
reddish.     The  ground  color,  as  may  lie  seen  in  abraded  specimens,  is  really  black,  and  the 
apparent  color  is  due  to  scales  very  similar  to  those  of  butterflies  and  moths. 
[Cir.  09] 


I  ill     l   vin.l  R   CHESTNl  1     WEEVIL. 
i  liiiln ii in u  i  pruboacidcu*   Pub  > 

The  larger  chestnut  weevil  (fig.  2)  is  considerably  the  larger  and 
more  robust  species.  The  female  rostrum  or  beak,  although  proportion- 
ately of  about  the  same  length 
as  in  the  lesser  w  ec\  il,  ia  per 
ceptibly  more  prominent  !»• 
cause  l«'--  curved,  the  cur\  at  ure  • 
being  toward   the   tip.     Ii    ia  rv    ^V     ri 

also  more  w  idened  at  the  base. 
The  body  measures  From  < m*>- 
third  to  nearly  one-half  of  an 
inch  in  length,  and  the  beak 
of  the  female  is  often  five 
eighths  "I"  an  inch  long.  That 
of  the  male  i  fig.  ■_'.  i  )  ia  nearly 
as   long  as   the   elytra.     The 

IS     small,     RDOUl     One-six-^o  n>.    largei  chestnut  weevil 

,        ..  ,     |  i       ,-      ■  'i   Female  beetle;  b,  lame  in  ootllne   from 

(eenth  Of  an  inch   long,  and  <>l      .  andantenna  of  male 

the     Outline     shown     in     figure      ttmea  natural  atse  (author's  UlustraUon 

."..</.     It  is  nearly  white,  partially  translucent,  and  without  sculpture. 

The  larva  <  fig.  3,  a )  is 
milk-white,  robust,  fully 
three  times  BS  Long  as  wide. 

with  the  dorsal  or  upper 
portion  rounded  and  con- 
vex. The  entire  surface  is 
very  st  rongly  \\  rinkled 
transversely,  and  there  are 

Kn.   :i    -Larger  chestnut  «■■  g    \\-\\    \crv  -hort    hair-  -cat- 

a,  Lai  muli'  papa;  ■'.  »•«*     all  enlarged  (an-  ' 

tbar'ininitraUon  tercd   sparsely  over  the  dit- 

t'erent  segments.     The  head  i  tin.  1 1  i-  about  one-fourth  as  wide  as 

the  widest  portion  of  the  body.     It  i-  provided  with 

shorl  Inn  strong  mandibles,  by  means  of  which  it  gnaws 

the  kernel  constituting  it-  food.    The  fully  developed 

larva  in  ordinary  resting  position  measures  nearly  half 

an  inch.     Although  the  larva  has  do  true  legs,  it  i-  able 

to  crawl,  -lowly  and  clumsily,  it   i-  true,  by   mean-  of 

of  the  flattened  lower  surface,  locomotion  being  aided 

l'\  transverse  wrinkle-. 

The  pupa  i-  of  a  clearer  whitish  color  than  the  larva, 
and  -how-  the  principal  external  organs  of  the  body  of      nioatmtlon  • 
the  future  beetle,  all.  except   the  beak,   folded  tightly  t<>  the  l»od\ 
The  female  pupa  i-  illustrated  in  figure  3,  '-.    . 

[Ctr.  '.'•.'] 


•  'i  in  ii* 

Unch  en- 


This  species,  like  the  other  weevils  under  consideration,  is  native  to 
America  and  is  known  from  Rhode  Island  to  Virginia,  the  District  of 
Columbia,  southern  Ohio,  and  Tennessee,  and  westward  to  Kansas. 
The  geographical  distribution  of  this  and  the  other  nut  weevils  has  as 
yet  not  been  carefully  studied,  hut  in  all  probability  it  is  considerably 
more  extensive  than  above  stated. 

In  some  regions  this  species  is  quite  generally  known  as  the  chin- 
quapin weevil,  hut  the  investigations  conducted  during  L904  indicate 
that,  although  it  hreeds  in  chinquapins  and  more  commonly  in  chest- 
nuts, it  occurs  in  greater  abundance  in  the  larger  imported  nuts. 

THE    LESSER    CHESTNUT    WEEVIL. 

i  Balaninus  /(tin*  Saj .  i 

The  lesser  chestnut  weevil  (fig.  5)  has  the  scape  of  the  antenna 
longer  than  in  the  preceding  species  and  the  first   joint  longer  than 

the  second."  The  average 
length  of  the  body  is  about  one- 
fourth  of  an  inch,  hut  the  size 
varies,  as  in  all  of  these  insects. 
The  distribution  of  this 
specie-  extends  from  Canada 
and  Massachusetts  to  North 
Carolina.  Tennessee,  and  Ohio, 
ami  probably  farther  west- 
ward. The  writer  ha-  seen  sets 
of  specimens  labeled  "Arizona." 

Although  in  some  localities  the 
Pig.  5. — Lesser  chestnut  weevil    i  Balaninui    rectus)    1  ■        ■  i_ 

adult:  a,  Female,  dorsal  view;  b,  female,  lateral  liU^'1'  SPeCleS  lS  lllll(;h  ln°n'  U1 
view;  c,  head  of  male.  Much  enlarged  (author's  evidence,  taken  all  ill  all.  the 
illustration).  i  ■.    •      tl 

lesser  weevil  is  the  more  com- 
mon and  is  probably  even  more  widely  disseminated. 

The  egg  has  not  come  under  observation,  but  is  undoubtedly  very 
similar  to  that  of  the  preceding,  being  proportionately  smaller,  which 
is  true  of  the  remaining  stages. 

The  larva  is  only  a  third  of  an  inch  long  and  its  length  is  about 
three  times  its  width.  The  body  is  milk-white  and  the  head  light 
brownish  yellow,  while  the  i-mark  has  a  short  lateral  branch  each 
side. 

The  pupa  differs  from  that  of  the  larger  species  by  size  and  by 
characters  shown  in  figure  6,  which  illustrates  the  male. 

"  In  the  larger  species  the  first  joint  (omitting  the  scape)  is  shorter  than  the 
second.     In   the   female  rectus  the  rostrum   is  strongly  curved,   the  thorax   is 
longer  than  wide,  and  the  elytra  are  strongly  acuminate  apically.     The  tooth 
with  which  the  thighs  are  armed  is  small,  with  the  entering  angle  rounded. 
[Cir.  99] 


1  I II      MOTOR  1     '   l      BOTH    8P]  i   1 1  -. 

rhe  life  history  of  our  two  chestnut  weevils  is  so  similar  as  to  be 
practically  the  Bame  for  both  species.  There  are,  however,  minor 
differences.  These,  as  well  as  r<  lated  mil  and  acorn  weei  ils,  hibernate 
exclusively  in  the  larval  condition  and  in  the  soil.     Both  make  their 

Rrsl  appearance  ai  about  the  same  time     with  the  first  bio g  of 

chestnuts    but    this   period    may  varj   from    late   in   June   to  July, 

according  to    locality   and    season,  or,  more    properly    speaking,  the 

mean  temperature.     At   this  time  the  beetles  are  found  rarely  and 

scatteringly,  and    as  oviposition    has  not    been  observed    then    ii    is 

doubtful  whether  it  begins  until  considerably   later.     What   function 

these  early  arrivals  fulfill  is  problematical.     The  beetles  increase  in 

number  as  the  nuts  approach  maturity,  or  until  about  the  middle  of 

September  or  a  little  time  before  the  nuts  are  first  marketed.     Then 

they  max  be  seen  in  greater  abundance,  several  pairs,  frequently  of  both 

species,  often  occurring  on  a   single  bunch 

of  burrs  |  fig.  8).     A-  it  requires  about  two 

weeks  for  the  egg  to  develop,  it  is  not  prob 

able  that  the}   are    laid    much  earlier  than 

when  the  nut  begins  to  form.     Prom  exam 

ination  of  many  burrs  gathered  in  the  fall 

of  L904  by  Mr.  V.  C.  Pratt,  of  the  Bureau 

of   Entomology,  \\  ho   \  isited    some   of   the 

principal   chestnut    groves  of   Pennsylvania      K  »r  chestnui  weevil 

and  Virginia  at  the  urgent  r ,est  of  gro* 

ers  in  those    States,  it   is  deduced    that  the       riKl"    En    '  ai...r-. 

first  eggs  deposited    are  laid    (seldom  and       1""-tr,,l"•"  '• 
very  sparingly  |  in  the  soft,  woolly  material  surrounding  the  forming 
nut;  but  later  they  are  inserted  in  the  knurl  jusl  under  the  inner 
skin,  and  occasionally  they  are  deposited  somewhat  more  deeply.     In 
no  case  has  the  egg  I n  found  in  the  outer  husk. 

Eggs  are  laid  singly,  bul  many  are  placed  iii  a  single  nut,  as  high  as 
l"  or  more  (of  the  -mailer  weevil  i  in  imported  nuts,  and  as  many  as 
'•»  in  native  nut-.  The  larva;  when  hatched  feed  on  the  tissue  of  the 
growing  kernels,  enlarging  with  their  own  growth  the  cells  thus  made. 
W  hen.  as  i-  usual,  several  larvae  inhabit  the  same  nut,  the  interior  is 
more  or  less  completely  hollowed  out,  and  large  ma—-  of  excremenl 
are  left  behind  i  fig.  9). 

I'».\  the  en, |  of  September  or  the  first  weeh  of  October  the  beetles  dis- 
appear. At  about  the  same  time,  when  the  nuts  first  fall,  the  larva?  be- 
gin to  mature  and  issue  from  round  orifices  which  they  gnaw  through 
the  shell  and  which  vary  in  diameter  from  one-i  \teent  h  of  an  inch,  in 
the  case  of  the  -mallei-  species,  to  one-eighth  of  an  inch  in  the  larger 
(see  fig.  7 1.  By  the  size  of  these  hole-  alone  it  can  be  readily  deter- 
mined which  species  is  the  dominant  one  m  any  given  locality     Rarelv 

[Cir 


Fig.  7. — Chinquapins,  showing  injury  l>>  les- 
ser chestnut  weevil  at  left;  of  larger  weevil 
nl  right.     Enlarged  (original). 


larvae  bore  through  the  burr.  (>n  leaving  the  nuts  they  burrow  into 
the  earth  to  depths  varying  from  -2  to  about  8  inches,  according  to  the 
hardness  of  the  soil.  If  confined  in  soft  earth  or  sand  they  penetrate 
-till  deeper.  The  larval  period  probably  lasts  from  three  to  live  weeks 
in  the  nuts,  and  about  ten  months  m  the  earth,  pupation  taking  place 

within  three  weeks  of  the  issuance 
of  the  beetle,  the  latter  remaining 
several  days  in  the  earth  before 
appearing  above  ground. 

The  beetles  do  not  fly  readily,  but 
cling  tightly  to  their  resting  place 
or  drop  when  disturbed:  yet,  as 
their  bodies  are  not  heavy  and  their 
winirs  strong,  they  are  obviously 
able  to  cover  considerable  distances, 
especially  with  the  wind.  Ordina- 
rily, however,  they  are  sluggish, 
like  most  other  weevils,  and  probably  do  not  go  far  from  the  vicinity 
of  the  trees  which  have  sheltered  them  as  larvae,  although  they 
undoubtedly  migrate  when  food  is  scarce. 

NATURAL    ENEMIES. 

A  natural  enemy  of  the  nut  weevils  is  known,  a  small  four-winged 
wasplike  fly,  the  braconid  parasite  Urosigalphus  armatus  Ashm.. 
which  develops  in  the  body  of  the  larva. *: 

METHODS    OF    CONTROL. 

The  most  practical  remedy  for  nut  weevils  that  can  be  suggested  is 
the  early  destruction  of  the  "  worms"  in  the  nuts  by  means  of  bisul- 
phid  of  carbon  and  the  observance  of  clean  orchard  management  and 
other  cultural  methods.  It  may  be  well  to  preface  the  discussion  of 
these  methods  with  a  statement  of  the  uselessness  against  nut  weevils 
of  ordinary  measures  employed  in  the  control  of  similar  insects. 

Unsatisfactory  Methods. 

Stomach  poisons. — The  peculiar  structure,  in  the  nut  weevils,  of 
the  mouth-parts  (minute  mandibles  placed  at  the  end  of  a  beak  nearly 
as  fine  as  horsehair  and  as  long  or  longer  than  the  body)  is  almost 
sufficient  proof  in  itself  that  these  insects  do  not  feed  on  leaves,  but 
depend  for  sustenance  on  the  substance  of  the  growing  nuts.  The 
beetles  first  appearing  feed  on  the  undeveloped,  very  young  nuts  and 
the  juices  within  the  husk.  There  is.  therefore,  no  seeming  possibility 
of  reaching  them  with  a  spray  of  Paris  green  or  other  stomach  poison. 

"Two  other  insects  are  associated  with  the  weevils  and  are  probably  also 
their  enemies,  n  proctotrypid  parasite.  Trichasis  mflpes  Ashm.,  ami  a  predatory 
reduviid  bug,  Acholla  multispmo&a  Dec. 
[Cir.  99] 


FN 


B      i.;ir:'T  chestanl  \% •  •  •  ■  \  i I  "ii  chinquapin  barn      Twice  n:itm-:il  b1k   (original). 
[Or.  !>!>1 


PIG.  9. — Imported  nuts,  showing  different  forms  of  injury  by  nut  weevils.  1 — Parry's 
Giant  nut,  showing  exit  hole  of  Balaninus  probosddeus ;  2 — Same  of  /;.  rectus:  :> — 
Interior  of  Paragon  nut,  showing  larva'  of  H  rectus  in  situ;  4 — Same,  showing  work  of 
one  individual  of  /(  proboscideus ;  6 — Reverse  side  of  figure  2.  showing  sears  made  by 
puncture  of  female  n  rectus  in  ovipositing:  6 — Reverse  of  figure  l.  with  puncture  of 
/{.  proooscidetw.  All  natural  size  (original). 
[Cir.  99] 


particularly    as  we  are  unable  to  place  the   insecticide   where  they 
« until  iii  enough  to  kill  i hem. 

Trap  crops.  The  cultivation  '>f  special  varieties  of  nut-  with  a 
view  to  securing  immunity  from  attack  or  as  ;i  means  of  luring  the 
insects  from  the  main  crop  does  not  offer  any  degree  of  promise.  The 
Paragon,  Cooper,  and  Ridgele}  varieties,  according  t"  Mr.  <■  II 
Powell,  of  the  Bureau  of  Plant  Industry,  suffer  greater  1"--  from 
weevil  attack  than  Japanese  varieties.  Chinquapins  are  favored  l>\ 
the  smaller  weevil  and  suffer  far  more  damage,  as  a  rule,  than  wild 
chestnuts.  Ii  is  possible  thai  the  planting  of  the  varieties  specified, 
or,  better,  of  chinquapins,  at  intervals  around,  as  also  through, 
orchards  of  the  leasl  affected  varieties  might  lessen  the  loss  to  the 
main  crop.  If  a  variety  could  be  produced  which  would  mature  fruit 
before  the  advent  <>t'  the  beetles  in  greatest  numbers,  tin-  would 
partially  solve  the  problem,  particularly  as  the  earliest  nuts  bring 
the  highest  prices.  The  nuts  gathered  toward  the  end  of  the  season 
are  comparatively  uninjured,  l>m  by  this  time  the  market  value  is 
considerably  lower. 

(uni M  i  poisons.     Scarcely  more  can  be  expected  from  the  use  of 
contact  poisons,  such  a-  kerosene  emulsion,  since  in  view  of  the  long 
period  spent  by  these  weevils  in  the  adult  stage  ( from  June  and  July 
to  September  or  October)  such  frequent  application  would  be  ui 
Bary  that  the  expense  would  destroy  the  profit. 

Jarring  mr  nusES,  as  practiced  againsl  the  plum  curculio,  is  for 
the  same  and  other  reasons  equally  impracticable,  save,  perhaps,  on 
young  tree-  grown  in  a  -mall   way. 

I'm  w  \  1 1 1:  it  —  i  -  m  i  mi  -i  \  i  H  in.  Having  doubts  of  the  efficacy  of 
this  old-fashioned  test  of  the  difference  between  ■•wormy"  and 
healthy  nut-,  an  experiment  was  made  by  the  writer  witli  native 
chestnuts  obtained  from  a  street  vender.  To  begin,  I"  per  cent  were 
obviously  "  wormy."  ami  only  60  per  cent  apparently  sound. 

Results  of  water  tests  icith  nai  tnuts. 


i  iiirti  rose  • 

Unlnfwted 

I  Ing  minute  marks  only:  good 

Vrr  cn<  . 

■ 

10 
80 

In  norfivt  condition 
Slightly  injure! 

Completely  iiium  with  grata 

Per  cent . 

10 

30 
20 

lining  full  irmu  n  grabs 
linlnc  Immature  grata 

A-  will  be  -ecu  from  this  experiment,  noticeably  wormy  nut-,  as 
evidenced  by  loss  of  weight  and  the  exit  holes  of  the  "worms," 
naturally  rise  when  placed  in  water.  l>ut  the  remaining  nut-  may  or 
may  not  he  infested,  and  hence  require  further  test  than  whether 
they  will  -ink  or  float, 
[dr.  '.''.'l 


10 


I  >iiu.<  t  Remedies. 


Bistjlphid  of  carbon. — The  value  of  bisulphid  of  carbon  as  a  fumi- 
gant  for  chestnuts  infested  by  weevils  is  now  fully  established. 
Although  at  first  thought  it  would  seem  difficult  for  the  gas  to  pene- 
trate through  shells  so  firm  and  compact  and  kill  the  larvae,  neverthe- 
less  a  prominent  grower  in  Pennsylvania  successfully  uses  the  bisul- 
phid, applying  it  when  the  nuts  are  first  harvested.  The  dead  weevil 
larva'  are  at  this  time  so  small  that  the  average  person  would  never 
detect  their  presence,  while  if  they  were  permitted  to  develop  they 
would  soon  destroy  the  nut  for  food.  Bisulphid  of  carbon  has  been 
used  on  the  largest  chestnuts  grown  in  this  country,  and.  since  a  score 
or  two  of  larva'  find  shelter  in  a  single  nut.  one  can  appreciate  the 
desirability  of  prompt  fumigation.  The  grower  mentioned  uses 
bisulphid  of  carbon  at  the  rate  of  1  ounce  to  a  bushel  of  Paragon  nuts 
placed  in  a  kerosene  barrel  of  about  50  gallons  capacity  and  covered 
by  sacking.  After  an  exposure  of  about  sixteen  hours  the  nuts  are 
removed,  the  larva'  being  then  practically  all  destroyed.  Several 
hundred  pounds  were  treated  in  1901  in  this  manner  with  perfectly 
satisfactory  results.  To  verify  reported  results.  Mr.  Pratt  was 
detailed  to  visit  the  infested  orchard  and  witness  the  process.  This 
method  could  be  employed  at  less  expense  by  using  tightly  fitting 
covers,  the  effectiveness  of  the  fumigation  being  in  exact  proportion 
to  the  tightness  of  the  receptacle  and  the  length  of  exposure  to  the 
fumes.  Therefore,  a  longer  exposure  of  one  or  two  days,  with  per- 
haps one-half  ounce  of  bisulphid.  should  accomplish  the  same  purpose. 

Scaldino  and  DRYING. — Some  growers  make  a  practice  of  plunging 
the  nuts  as  gathered  into  boiling  water  just  long  enough  to  kill  the 
contained  insects  and  yet  not  injure  the  nuts  for  sale,  after  which 
they  are  dried  before  being  marketed.  This  may  be  profitably  accom- 
plished by  using  a  large  sieve,  which  is  filled  with  nuts,  dipped  in  the 
water,  and  removed  in  about  five  minutes.  The  late  W.  P.  Corsa 
used  a  washtub,  in  which  was  placed  a  bushel  or  so  of  nuts,  pouring 
in  enough  boiling  water  to  come  an  inch  or  two  above  the  nuts. 
Then,  by  stirring  vigorously  with  a  stick,  the  bulk  of  the  weevilly 
nuts  would  come  to  the  surface  in  the  same  manner  as  do  peas  and 
beans  affected  by  weevils.0  The  infested  nuts  are  skimmed  off  and 
destroyed,  or  they  may  with  profit  and  safety  be  fed  to  hogs,  pro- 
vided the  animals  do  not  have  a  too  exclusive  diet  of  this  form  of 
food.  Salt  water,  it  is  claimed,  is  preferable  for  scalding,  the  brine 
serving  to  keep  the  shell  soft  and  pliable  and  rendering  the  kernels 
more  palatable  than  when  not  thus  treated. 

Different  methods  are  employed  in  drying.  A  good  way  is  to  place 
the  nuts  in  the  sun  and   agitate  them   occasionally  by  stirring  or 

"  .Note  the  writer's  observations  on  this  head  on  p.  '.». 
[Cir.  99] 


11 

shaking  in  a  bag  until  thoroughly  dry,  because  it  moisture  remains 
unevaporated  it  is  apt  t°>  form  mildew  when  the  nuts  are  prematurely 
packed    for  shipment. 

\ut-  for  planting  should  i><>i  !>«•  scalded,  and  care  should  be  taken 
iidi   to  cook  the  kernels  of  nuts  intended   for  sale.     Sum.-  growi 
claim  thai  the  hot  water  treatment   is  objectionable  because  the  nul 
shells  lose  a  certain  degree  "f  polish,  rendering  them  less  desirable 
for  market. 

Heat.  Infested  nuts  can  !><•  subjected  t<»  a  temperature  of  be- 
tween L25  F.  and  150  I",  without  injuring  them  for  food  or  for 
-ci'd.  Mini  tin-  will  effecl  the  destruction  of  the  larva;  within.  Some 
growers  of  chestnuts  destroy  the  weevils  by  kiln-drying. 

Cold  storage.  Cold  storage  has  been  employed  and  is  successful 
in  arresting  the  development  of  the  larva?.  The  appearance  of  the 
nuts  is  scarcely  different  from  that  of  those  not  so  stored,  but  nuts 
thus  treated  and  submitted  to  the  writer  after  becoming  dry  were 
deficient  in  flavor,  having  an  acrid  and  moldy  taste. 

\  crude  form  of  cold  storage  has  been  successfully  followed  by  a 
Virginia  grower.  It  consists  in  placing  nuts  in  the  earth  under  the 
-hade  afforded  by  his  house,  where  the  soil  temperature,  after  the 
nuts  are  gathered,  doe-  not  exceed  ">11  .  Since  most  insects  are  ina< 
live  below  51  thi-  has  the  effecl  of  restraining  their  development, 
causing  the  eggs  or  minute  larva;  to  die. 

Phi  \  i  \  i  m  i  -. 

Choice   of   ux  IlTion    fob   mi    orchard.      The    -election    for   the 
planting  or  grafting  of  chestnuts  of  a  locality  with  reference  to  the 
chance-  of  immunity  from  injury  by  nut  weevils  is  a  matter  of  great 
importance.     For  this  reason  it  i-  most  undesirable  to  plant   in  the 
immediate  vicinity  of  woodland  abounding  in  wild  chestnut  and  chin 
quapin,  since  these  trees  furnish  natural  breeding  places  for  the  in- 
sects, and  are,  therefore,  a  constanl   menace  to  successful  chestnut 
culture.     Too  frequently  growers  suffer  losses  from  weevils  because 
they  neglect  to  gather  the  wild  chestnuts  or  chinquapins  in  the  im- 
mediate vicinity  of  their  cultivated  groves.     Another  phase  of  had 
management  which  i-  frequently  practiced  is  the  grafting  of  culti- 
vated varieties  on  native  chestnuts  growing  in  rocky  and  uneven  soil, 
often  on  hillsides,  as  shown  in  figure  11.    In  such  place-  it  i-  impos 
sible  to  har\e-t  a  complete  crop.  and.  what  i-  of  equal  importance,  to 
gather  the   remnant-.      Hence,   to  secure   these   results,   it    is   impera- 
tive to  plant  or  graft  trees  on  smooth  ground  (fig.  12),  tir-t  for  the 
sake  of  economy,  and  second  to  permit  the  collection  of  all  of  the 
nuts,  leaving  none  for  the  propagation  of  weevil-.     It  is  also  neces 
sary  to  keep  the  soil  clean  of  herbage,  as  shown  at  the  left  of  fig 
ure  L2 — not   overgrown  with  brush,  a-  illustrated  at  the  right. 

[Clr    !)!»] 


12 


Careful  harvesting. — It  is  always  advisable  to  gather  the  entire 
crop,  leaving  none  on  the  ground,  and  cither  place  the  nuts  in  ti<rht 
receptacles  or  fumigate  with  bisulphid  of  carbon  before  marketing. 
The  grubs  crawl  out  soon  after  the  nuts  have  been  gathered,  and  as 

they  require  considerable  moisture  they  will  die  ii'  confined  in  closed 
barrels  or  boxes.  The  trouble  is  that  enough  nuts  are  usually  left  in 
orchards  or  in  adjoining  wood  or  forest  land  to  serve  for  the  propaga- 
tion of  the  insects  the  following  year.  In  order  to  make  the  method 
of  treatment  here  described  thorough,  it  will  be  necessary  to  secure  the 
cooperation  of  neighboring  landowners  who  grow  chestnuts  for  mar- 
ket and  of  all  who  own  woodland  containing  chestnut  and  chinquapin. 

The  collection  of  remnants  can  be  made  by  children  or  the  unem- 
ployed. It  is  also  profitable  to  allow  hogs  the  run  of  the  orchards  to 
destroy  what  nuts  remain  after  the  crop  has  been  harvested.  In  the 
mountainous  sections  of  Virginia  and  Pennsylvania  it  is  a  common 
practice  to  fatten  swine  on  the  unpicked  fallen  nuts.  Hogs  fatten  on 
nuts  and  acorns  as  well  as  on  corn,  and  without  expense  to  the  grower. 

Cooperation. — The  results  of  the  observance  of  clean  farming  on 
the  lines  that  have  been  indicated  may  not  at  once  be  apparent,  but  in 
course  of  time,  if  this  work  is  systematically  carried  out  by  all  grow- 
ers over  a  considerable  territory,  infestation  will  be  very  materially 
decreased.  An  important  point  is  to  ascertain  how  far  the  insects 
fly.  Their  structure  indicates  that  they  are  strong  fliers  and  capable, 
with  favoring  winds,  of  migrating  considerable  distances;  but  under 
ordinary  circumstances  they  probably  do  not  fly  many  miles  at  a 
time  or  in  a  given  year. 

The  Pecan  Weevil. 
(Balaninus  oaryx  Horn.) 
With  the  increase  of  pecan  culture  in  our  southern  States  frequent 
inquiry    is   made   in   regard    to   the   cause   of   the   holes   in    the   nuts 

(fig.  10).  and  during 
IDO.i  and  1904  there 
were  reports  of  great 
injury  of  this  nature, 
more  particularly  to 
pecans  grown  in  Texas, 
where  considerable  loss 
was  reported,  and  in 
Georgia,  where  in  one 
locality  7.">  per  cent  of 
the  crop  was  a  failure. 
A  shortage  has  also 
been  reported  in  Mis- 
sissippi. The  insect  involved  in  these  cases  is  the  pecan  or  hickory- 
nut  weevil,  a  pest  which  is  evidently  destined  to  become  one  of  the 
[Cir.  !)'.)] 


Fig.  in. 


-Pecan  nuts  showing  exit  hole  of  pecan  weevil  larva-. 
One-third  enlarged  (author's  illustration!. 


i:: 


Pia    1  I       I  'aragon  cbekl  nut  orcl 

bard  management, 


Paragon  chestnut  growing  on  plan.'  surface,  where  dean  methods  of  cultivation 

i  an  be  practiced. 
I  fir.   DO] 


14 


principal  drawbacks  to  the  cultivation  of  the  pecan.  Indeed,  in  many 
parts  of  the  South  it  already  divides  that  distinction  with  the  husk- 
wonu.  so  that  it  has  been  truthfully  said  that  what  the  husk-worm 
leaves  the  weevil  destroys. 

The  beetle   (fig.  13)   is  about  the  same  size  as  the  larger  chestnut 
weevil,  from  which  it  may  he  distinguished  by  its  much  duller  color0 
and  by  the  relative  lengths  of  the  first  and  second  antenna]  joints,  the 
first  joint  being  longer  than  the  second  in  the  pecan-infesting  specie-. 
The  larva  differs  from  that  of  proboscideua  in  heing  decidedly  yel- 
low, having  the  head   bright 
red  and  wider  than  long.     Its 
cervical  plate  also  is  darker. 
The  pupa  is  similar  to  that  of 
the  larger  chestnut  weevil. 

The  distribution  extends 
from  New  York  to  the  (iiilf. 
and  westward  at  least  to  Iowa. 
The  life  history  of  this  wee- 
vil, as  it  occurs  in  the  pecan 
in  the  South,  is.  so  far  as  can 
be  gathered  from  reports  from 
Georgia  and  Texas  and  from 
laboratory  experiments,  very 
similar  to  that  of  the  chestnut 
weevils.  According  to  the  ob- 
servations of  Mr.  H.  A.  Halbert.  at  Coleman.  Tex.,  the  female  begins 
to  deposit  her  eggs  in  August  while  the  pecan  is  still  immature,  and 
the  larva  usually  escapes  from  the  nuts  in  the  latter  part  of  Septem- 
ber and  in  October;  but  most  of  them  do  not  issue  until  the  husks 
open,  allowing  the  nuts  to  fall.  In  Georgia  they  have  been  found  in 
the  nuts  as  late  as  the  middle  of  January. 

REMEDIES. 

The  same  care  in  the  selection  of  the  site  for  a  pecan  orchard  is 
advised  as  in  the  case  of  chestnut  culture,  with  this  difference,  that  the 
grower  should  avoid  planting  in  the  vicinity  of  wild  pecan  and  hick- 
ory of  whatever  kind.  The  entire  crop,  also,  should  he  harvested  or 
hogs  should  be  turned  in  to  devour  what  nuts  are  left.  At  Thomas- 
ville,  Ga..  Mi-.  YVilmon  Newell  observed  in  L904  that  where  swine  ami 
chickens  had  had  access  to  a  pecan  grove,  the  ground  was  well  rooted 
and  scratched  up  and  there  was  less  Loss  from  weevils  than  in  the  pre- 

"  Tlie  ground  color  is  uniform  dark  In-own.  nearly  black,  and  the  scaly  covering 
i  which  characterizes  the  chestnut  weevils)  in  this  species  is  hair-like  on  the 
thorax,  line  and  somewhat  sparse  on  the  wing-covers,  and  much  duller,  with 
little  or  no  mottling.  Moreover,  the  beak  of  the  female  is.  comparatively,  a  little 
shorter,  although  of  about  the  same  curvature,  and  is  less  widened  at  the  base. 
[Cir.  !':>] 


Fig.  13. — Pecan  weevil  (Balaninus  caryse):  a,  Female. 
dorsal  view;  b,  same,  lateral  view,  in  outline; 
c,  head  with  rostrum  and  antenna  of  male.  About 
two  and  one-half  times  natural  size  uiuthor's 
illustration). 


15 


vious  year.    Evidently  both  hog    and  poultry  devour  the  larva?  in  the 
ground. 

At  the  time  that  bisulphid  of  carbon  was  first  suggested  as  a  remedy 
for  chestnut  ''worms"  if  was  feared  thai  the  firm  and  compact  shell 
would  hardly  permit  the  gas  to  penetrate  and  kill  the  contained  larva). 
Experience,  however,  has  shown  that  this  remedy  ia  successful  in  the 
case  of  chestnuts,  and  it  is  not  impossible  tliat  it  might  be  adapted  to 
pecans,  using  ;i  larger  amount  of  the  chemical  and  a  longer  exposure 
in  a  perfectly  tighl  receptacle.  We  can  as  yet  scarcely  advise  this 
method  on  a  large  scale,  but  it  should  certainly  be  tried  experimentally. 

Tin    1 1  \/i  i.m  i   W  ii  \  ii.. 
(Balaninut  obtusua  Blanch.) 
Hazelnuts  or  filberts  are  injured  in  much  the  -nine  manner  as  are 
chest  11  in-  and  pecans  and  by  ;i  similar  weevil.    Injury  was  recognized 
:i-  early  as  1841,  !>ut  was  attributed  to 
other  species  than  that  under  considers 
t  ion.    Owing  to  the  comparatively  slight 
importance  of  the  hazel  as  a  nut  tree  in 
this  country,  few  notices  of  losses  from 
weevil  attack  have  been  recorded.    The 

weevil  which  ailed-  the  nut  was  not 
differentiated  from  others  of  its  kind 
until  1884.  In  1891  ii  was  reported  as 
badly  damaging  hazelnuts  in  Iowa 

The  beetle  (  fig.  1 1 )  differs  from  others 
which  attack  edible  nuts,  exclusive  of 
acorns,  by  its  shorter,  more  robust  form 
and  shorter  beak.'  It  is  about  one- 
fourth    of  an    inch    in    length,   and    the 

beak  doe-  nol   exceed   half  the  length  of  the  body.     The  vestiture 
raries  from  gray  to  ochreous',  and  the  elytra  are  moderately  mottled. 

This  species  occur-  from  Massachusetts  and  New  Hampshire  west- 
ward to  Minnesota  and  Texas.  Injury  has  been  noted  in  Massachu- 
setts, New  York.  Indiana.  Iowa,  and  Minnesota. 

Of  the  life  history  little  has  been  recorded  beyond  the  fact  thai  the 

"  worm  "  issues  from  the  -ide  of  the  nut.  and  that  paired  adult-  have 
been  found  on  hazelnut-  in  duly. 

1:1  mi  mi  -. 
Since  hazel-  are  not  cultivated  in  this  country  to  any  extent,  no  rem- 
edy need  be  employed  other  than  gathering  entire  crops  and  destroy- 
ing isolated  bushes  where  it  i-  unprofitable  to  gather  the  nut-.     It 

would  he  quite  possible,  owing  to  the  -mall  size  of  the  hazel  plant,  to 
control  this  species  by  jarring,  a-  for  the  plum  curculio. 

■"Tin-  appendices  of  tin'  claws  are  broadlj    rectangular,  and  the  femora  or  thlgl 
arnuMl  with  large  teeth     The  scape  at  the  antenna  in  ti\.-  female  i-  long. 


Fig,  i  i  —  Haaalnnl  tfaninui 

aofwiM  .  adult:  a,  Female,  •icr-jii 
vi.u  ,  ;.  head  from  side  ■  bead  of 
male  from  side,    Enlarged  (original  i. 


I  fir    '.>!>] 


o 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  5603 


